As a Poser user, I have to say that Blender Cycles has a much better render engine ;). But for that it takes knowledge and work ;). And like Paolo has pointed out, it's definitely levels of magnitude more complicated than Poser is :). Worth it to learn, I feel, but not going to happen overnight for certain.

Having said that, while I know that Pret-a-3D is trying to sell his product, there are free options to get things from Poser to Luxrender, as I described in another thread :).

Laurie